Abstract: A hydraulic brake system for automotive vehicles with at least one load sensor (41) sensing the load condition of the vehicle and with at least one sensor (14, 15, 21, 22) associated wtih each vehicle axle for the detection of a braking parameter decisive for the braking operation. The measured values sensed are supplied to an electric evaluation circuit (18) which during a braking operation permanently computes suitable braking pressure values for the wheel brakes (3, 4) of the rear axle and delivers corresponding control signals to a braking pressure modulator (31, 53, 54). A braking force sensor (14, 15, 21, 22) is associated with at least one vehicle wheel (12, 13, 19, 20) of each vehicle axle.

Abstract: A brake booster (10, 210, 310) connected to a control circuit (120) provides for continued braking of a vehicle when the vehicle is situated on an incline and the brake pedal (92) is released by the operator. Continued brake application is accomplished by utilizing a control circuit (120) responsive to vehicular attitude, clutch pedal position, ignition status, vehicular speed, and vehicular direction. The control circuit (120) is connected to a combination check valve and three-way solenoid valve (100, 200, 300) connected to a movable wall brake booster (10, 210, 310). The combination valve (100) is connected to a flexible hose (110) disposed interiorily of the booster (10), the other end of the flexible hose (110) connected to the input opening (32) of a three-way poppet valve (70) located at the central hub (30) of the booster (10).

Abstract: An improved booster for use with a master cylinder in a brake system is proposed which includes a spring for keeping the input shaft away from the booster piston. The spring has one end abutting on a piston acted by the auxiliary pressure from the auxiliary power source and the other end abutting on the brake pedal to bear the pedal stepping force. The input shaft will not engage the booster piston except in case of the failure of the auxiliary power source, ect.

Abstract: A hydraulic brake system for automotive vehicles with a master brake cylinder (51) and with a hydraulic power booster (49) connected upstream of the master brake cylinder, in which a pressure medium pump (18) which may be driven by an electric motor (17) is used for providing an auxiliary hydraulic energy, the drive of which may be switched on by a pressure accumulator (1), on the one hand, and by a brake pedal contact (58), on the other hand, in the unbraked operation of the automotive vehicle the pressure accumulator (1) permanently being kept on a pressure level sufficient for an initial actuation of the brake and the charge of the pressure accumulator (1) being monitored by a pressure control valve (19).

Abstract: A method and a multi-circuit brake booster for feeding back disruptions of any arbitrary kind, even of an associated anti-skid brake system, to a then-changed brake pedal characteristic, the influence on the brake valve triggering being effected via a travel simulator device. The transmitting member in the travel simulator device is a travel simulator spring enabling a predetermined idle pedal travel, and this spring responds whenever, in response to an arbitrarily generated disruption signal, a lockable storage element assumes its other position and mechanically engages a transmitting member in the chain from brake pedal actuation to brake valve slide actuation in an arresting manner. Upon reaching a predetermined amount of biasing, as a result of the further compression of the travel simulator spring, the opening of the brake valve then takes place abruptly, with a corresponding increase in brake pressure and a corresponding increase in vehicle deceleration.

Abstract: A brake system wherein the piston (2) of a master cylinder (1) is actuated by the pressure controlled by a brake valve (6), a monitoring device is provided for detection of fail conditions. The monitoring device comprises a switch (18) which is closed by a trip cam (17) upon an actuating distance (s.sub.1) having been traveled by the actuating element (4), and further switches (20, 21), the switch (20) being closed after an actuating travel distance (s.sub.21) and the switch (21) being closed after an actuating travel distance (s.sub.22), each by a trip cam (19) at the master cylinder piston (2). If the master cylinder piston (2) has not yet traveled the actuating distance (s.sub.21) or has already traveled furher than the distance (s.sub.22) when the switch (18) closes, an evaluating circuit (22) which evaluates the positions of the switches (18, 20, 21) will switch on a signal lamp (23) to indicate a fail condition in the brake system.

Abstract: A brake booster can switch operating mode from a positive-pressure mode using a signal-controlled fluid pressure supplier to a vacuum-pressure mode and vice versa. The booster includes a booster converter holding both an air valve and a vacuum valve of the booster closed in the positive-pressure mode or holding the booster air valve in its closed and open positions while holding the booster vacuum valve in its open and closed positions respectively when the brake pedal is released and depressed in the vacuum mode. The fluid pressure supplier is enabled while both booster valves are in the closed position in the positive-pressure mode.

Abstract: An electrical switch for sensing operation of a hydraulic cylinder, the switch being normally open and closing an electrical circuit when the cylinder is pressurized to effect a desired operation only when there is fluid at a predetermined pressure in the cylinder. The hydraulic cylinder is the slave cylinder of a motor vehicle clutch hydraulic control and the electrical circuit controlled by the switch is, for example, the motor vehicle engine starter motor relay circuit, such that the starter relay circuit is inhibited unless sufficient pressure is present in the cylinder, corresponding to the pressure necessary to cause the slave cylinder output member to fully release the clutch.

Abstract: A main brake cylinder for vehicle brake systems, in which a control valve effects the application of an auxiliary force to at least one brake piston. Additionally engaging the control valve and supplementarily for possibly adjusting the brake pedal is an arbitrarily actuatable final control element, which is triggered by electrical signals of any desired form and duration. As a result, a feeding of pressure into the brake circuit is effected independently of the brake pedal actuation and as a function of electrical control signals, as a result of which a multiplicity of further possible applications of such a brake valve are afforded, for instance in order to realize a drive slippage regulation, self-diagnosis as to tightness, function, output and pressure supply, and stepped braking.

Abstract: An interlock switch mounted in the end of a hydraulic slave cylinder adapted to operate the release mechanism of a motor vehicle mechanical clutch, the slave cylinder being hydraulically connected to a master cylinder having an input member operable by the motor vehicle clutch pedal. The switch is adapted to close the motor vehicle starter relay circuit for a position of the slave cylinder output member corresponding to full release of the clutch, such that the clutch must be fully released in order to allow starting the motor vehicle engine. Preferably, the switch takes the form of a pair of concentric sleeves, each carrying appropriate contacts for closing the circuit, one of the sleeves being reciprocable in unison with the slave cylinder output member, and the other sleeve being automatically adjustable for initial position adjustment and for subsequent readjustment to compensate for wear of the clutch, such that closure of the switch always corresponds to a full release of the motor vehicle clutch.

Abstract: In a vehicle brake system including a pneumatic force multiplier apparatus in which a power piston moves by virtue of a pressure difference between atmospheric and negative pressure, a manual brake switch is provided to apply braking force without need for depressing the brake pedal. A controller includes a deceleration calculating circuit reading vehicle speed for every specified number of seconds and calculating the amount of deceleration. The deceleration is compared with a predetermined value and braking force is increased, maintained, or decreased depending on whether the vehicle is running on a downwardly sloping, level, or unwardly sloping road.

Abstract: An automatic brake actuator for motor vehicles which operates to activate the vehicle brakes at a predetermined rate and at a predetermined amount of force in predetermined conditions. In a particular embodiment, the brake actuator is controlled by an electrical control system which includes a switch in the driver's seat that automatically senses the weight of the driver when seated. The brake actuator may be connected to the vehicle's vacuum brake system and may be combined therewith by means of a unique electrically operated air control valve that is inserted in the vacuum brake air path. An additional electrically operated constraining air valve may be provided which insures that the brake actuator is activated gradually at (a predetermined rate) in order to avoid sudden hazardous stopping of the vehicle. The brake actuator control may include access to other vehicle functions such as theft alarm, etc. to prevent unwanted operation of the vehicle.

Abstract: A powered, electromechanical manipulator assembly is disclosed which includes an electrically powered input device coupled by a hydraulic circuit to a mechanical manipulator. The hydraulic circuit is a fixed-volume, closed circuit in which a master piston-cylinder assembly is driven by a D.C. motor and is hydraulically coupled for direct and proportional displacement of a slave piston-cylinder assembly to enable smooth, accurate and easily connected displacement of a manipulator arm. The manipulator arm is formed of a plurality of modules each having a fixed-volume, closed, hydraulic circuit and a slave cylinder. Both the slave and master cylinders includes ambient pressure surfaces which are exposed to the water pressure at the operating depth of the assembly so that variation in depth does not materially affect the response or dexterity of the remote manipulator apparatus. An improved terminal module or jaw assembly is also disclosed.

Abstract: A master cylinder includes a housing movably supporting a pair of pistons and carrying a fluid reservoir assembly. The fluid reservoir assembly carries a differential area piston and a float which cooperate to activate a single reed switch, thereby generating a warning signal for a vehicle operator.

Abstract: A hydraulic dual-circuit tandem master brake cylinder intended for use in brake systems of motor vehicles is proposed, to which a closed brake circuit (I) and an open brake circuit (II), the latter reinforced by auxiliary pressure, are connected. In order to switch the control valve, the main brake cylinder has a foot-actuated push rod as an actuation member, with transmission of force via a control contour or a travel-limiting spring, and it furthermore has an auxiliary piston member near the pedal, this member having an effective surface for making the feedback of the brake pressure which has been established perceptible. In this manner, a small, compact master brake cylinder construction which is very favorable in price is created. It is furthermore of advantage that the pedal characteristic is designed optimally in terms of human engineering. The main cylinder can also be used at little expense for an anti-wheel-lock apparatus as well.

Abstract: An auxiliary-energy-operable hydraulic brake system for automotive vehicles, in which a valve device connected to a pressure medium source and to an unpressurized reservoir and controlling an actuating pressure is operable by an actuating element which, irrespective of its direction of actuation, may be pressurized by a reaction force depending on the actuating pressure. The valve device is operable electromagnetically and controllable by an electric switching device connected with the actuating element.

Abstract: The present invention relates to a dual-circuit hydraulic brake system with slip control, in particular for automotive vehicles, wherein wheel brakes (26, 27, 41, 42) are connected via electromagnetically actuatable multiple-position valves (38, 39, 88, 40, 24, 89) to brake circuits which are hydraulically isolated from one another, wherein the brake circuits are adapted to be pressurized by a tandem master cylinder (1), on the one hand, and are connectible to a dual-circuit pump aggregate (76, 77) adapted to be driven electromotively, on the other hand. Both outlets of the pump aggregate (76, 77) are connected to normally closed brake valves (43, 44) which are governed by the master cylinder pressure and separating valves (11, 12) which are adapted to be closed by the outlet pressure of the brake valves (43, 44) are inserted into the connections between the tandem master cylinder (1) and the wheel brakes (26, 27, 41, 42).

Abstract: A brake control system in which the master cylinder has two pressurizing chambers for each brake circuit. Three brake circuits are disclosed in detail. One piston of each set of pressurizing chambers is directly applied by brake pedal force. The other piston of each set receives brake pedal force through resilient means, with additional force supplied by suitable servomotors. The servomotors are individually controlled to provide power-assist when appropriate, or to decrease the forces supplied by them to control wheel slip or wheel spin.

Abstract: A brake system for a vehicle comprises a booster unit including a power piston disposed slidably in a housing for defining a first chamber and a second chamber in the housing, a regulator disposed slidably in the power piston, a flow restrictor formed between the first chamber and a fluid pressure source for restricting flow of fluid in response to movement of the regulator, a pilot pressure chamber disposed upstream of the flow restrictor, a movable member moved by the internal pressure of the pilot pressure chamber thereby permitting communication between the second chamber and the fluid pressure source, and a reaction spring disposed between the power piston and the regulator. A master cylinder is connected to the power piston of the booster unit to supply braking hydraulic fluid at controlled pressure to front and rear brakes, and a brake pedal actuates the regulator of the booster unit to cause movement of the regulator relative to the power piston.

Abstract: A pump system is disclosed for delivering hydraulic fluid to a load device, such as a hydraulic brake system. The system automatically switches from larger displacement to smaller displacement as pressure at the outlet increases. The pump system comprises one or more lower pressure pumps and a high pressure pump with an actuator driving all pumps simultaneously. An unloading valve is coupled with each lower pressure pump for dumping the output thereof in response to pressure of the fluid delivered to the load device. The actuator comprises an electromagnetic linear motor which imparts an intake stroke to the pumps and stresses a spring which releases stored energy for imparting the pressure stroke to the pumps.

Abstract: To provide a power brake having relatively small hysteresis between brake pedal pressure and brake hose pressure and with compact construction, the push rod leading from the brake pedal to the brake master cylinder is divided into an input rod and an output rod. A pressure sensitive element is disposed between the rods and is displacable therewith. The pressure-sensitive element determines the force with which the servo member acts upon the output rod.

Abstract: A master cylinder for a two-circuit brake system which includes anti-skid control has two separate chambers and pistons. The main control piston is associated with an auxiliary piston which it engages after a predetermined amount of travel. The auxiliary piston has an extension which holds the brake control valve and which is opened by the control piston during its travel. Furthermore, the second circuit cylinder includes a pressure sensor which cooperates with double pistons which can activate a warning when the piston travel is not in a predetermined relation to the applied fluid pressure. Also included is an electronic switching circuit and associated valve mechanism for imparting a pulsating stroke to said double pistons.

Abstract: An improved pneumatic-hydraulic driving device for the knockout mechanism associated with the slide of a press-machine wherein the device serves to actuate the knockout mechanism in a controlled manner to provide cushioning motion during punching of the work, and knocking out motion after punching to permit removal of the punched work by a transfer machine, with the device being particularly useful in the fabrication of printed circuit plates wherein the device serves to decrease cycle-time of fabrication and increase quantity of production.

Abstract: In a dual master cylinder assembly comprising two independently and simultaneously operable master cylinders, primary pressure spaces between primary and secondary pistons are interconnected by a pipe-line, and secondary spaces between the secondary piston and adjacent ends of the master cylinders are connected to a common auxiliary braking system through a pipe-line. Each secondary piston is provided with an arrangement of passages in communication at all times with a reservoir for fluid, and normally open primary and secondary recuperation valves provide communication between the passages and the respective pressure spaces when the pistons are in their retracted positions. Simultaneous operation of both master cylinders causes both pairs of primary and secondary recuperation valves to close followed by pressurization of the fluid in both pairs of primary and secondary pressure spaces, whereby to apply simultaneously the brakes on opposite sides of the vehicle and to operate the auxiliary braking system.

Abstract: A brake booster is operated both by braking actuated by a brake pedal and by a solenoid. A moving core of the solenoid and a relay valve piston of the brake booster are linked by a balance lever, and the moving core of the solenoid has a much larger mobility than the relay valve piston during braking because the fulcrum of the lever is positioned nearer to the relay valve piston to enable the solenoid to be miniaturized. When the solenoid is actuated, the moving core requires much more time to move than to return. In an automobile equipped with this brake booster, the braking force can be increased gently but interrupted quickly during braking actuated by the solenoid.

Abstract: A rodless cylinder having a piston and an operation member slidable along the outer circumferential surface of a cylinder tube, each mounted with permanent magnets, and adapted to move the operation member along the cylinder tube by utilizing the attraction force between these permanent magnets, in which a plurality of individual magnets disposed axially to the cylinder in each of driving and driven magnet rows are arranged such that identical poles of the individual magnets are in adjacent to each other, and both of the driving and driven magnet rows are arranged such that the different poles of the individual magnets in each of the magnet rows are opposed to each other can provide a greater attraction force between the magnet rows with no changes in the size of the magnet and thereby reduce the size of the entire apparatus.

Abstract: A control system for a superhigh pressure generation circuit includes a hydraulic pump having a usual range of delivery pressure. An electrohydraulic servo valve controls the flow rate of pressurized fluid from the pump and supplies it to a primary side of a boost cylinder. A stepped piston slidably received in the boost cylinder strokes in response to the input fluid to generate a fluid pressure elevated in accordance with an effective sectional area ratio of the stepped piston in a secondary side of the boost cylinder. The fluid pressure in the secondary side is caused to coincide accurately with a reference pressure level on the basis of a feedback control.

Abstract: A braking apparatus (28) includes a housing (38). The housing (38) includes therein: a master cylinder section (40) for supplying pressurized fluid to the brakes (24) of an automotive vehicle (10) to effect a brake application, a hydraulic booster section (42) for assisting the master cylinder section (40) to effect a brake application, a fluid pumping section (44) driven by an electric motor, for supplying pressurized fluid to the hydraulic booster section (42), and a reservoir section (46) supplying a single fluid to the sections 40, 42, and 44. The electric motor driving the fluid pumping section (44) receives energy from the vehicle (10) only in response to a need for braking. The brake booster (28) includes a fluid pressure accumulator (147) providing pressurized fluid to the booster section (42) during a brake application. The accumulator (147) also provides for power-assisted braking in the event of a failure of the motor-driven pumping section (44).

Abstract: A short master cylinder uses solenoids to control the master cylinder compensating and bypass functions. The pressurizing pistons each use only one seal. There is a unitary primary piston and booster output push rod. The booster power piston return spring returns the primary piston and, through a lost motion interconnection, the secondary piston, omitting the secondary piston spring. Brake pedal travel and pressure sensors control the solenoid valves, reducing lost brake pedal travel.

Abstract: A method and apparatus for simultaneously adjusting the fluid pressures in a dual hydraulic circuit arrangement in which in a first hydraulic circuit pressurized fluid is supplied from a first pressure source to a first fluid pressure activated device and in a second hydraulic circuit pressurized fluid is supplied from a second pressure source to a second pressure activated device, comprising a cylinder having opposite closed ends and spaced bulkheads therein defining a central chamber between the bulkheads and a pair of chambers on respective opposite sides of the bulkheads. A pair of spaced first pistons are slidably mounted in the central chamber to define a control pressure chamber therebetween and first and second primary fluid pressure chambers between respective pistons and the bulkheads. The first primary fluid pressure chamber is connected to the first pressure source while the second primary fluid chamber is connected to the second pressure source.

Abstract: A power fluid system for a vehicle embodying a two-fluid pump which utilizes an existing source of fluid under pressure is provided. The existing source of fluid enables a second source of fluid under pressure to be established through the two-fluid pump. Vehicles often require high pressure fluid to operate auxiliary equipment such as traction or anti-skid units, limited-slip differentials, and hydraulic load-leveling systems. More specifically, the two-fluid pump is a linear pump operated by fluid under pressure from the power steering pump of the vehicle. The two-fluid pump can supply a different fluid under higher pressure for the auxiliary equipment, as required. The pump is pulse cycled quickly to provide adequate quantities of both sources of fluids with the use of small capacity accumulators.

Abstract: A hydraulic power brake system has a pump driven through a variable torque magnetic clutch by an engine-drive pulley. A rheostat controlled by movement of the brake booster push rod varies the amount of current to the clutch to control the torque transmitted to the pump. The pump pressure output varies directly with clutch torque. Pump pressure is delivered to a closed center hydraulic booster. The pump does not operate when no braking effort is required.

Abstract: The brake pedal force is amplified by an electric motor acting through a gear set which converts rotary motion and torque from the motor into linear motion and force to energize the master cylinder piston. The push rod forces are sensed, amplified, reduced and modulated by electronic means. The electric motor disengages from the gear set at rest or if there is an electrical failure, so that there is a manual mode of operation available when necessary.

Abstract: A remote control actuating mechanism for adjusting the angular position of an outside vehicle rearview mirror. The mechanism comprises a master control device and a slave device, each having a piston reciprocable within a cylinder. Closed hydraulic circuits connect the two devices so that when the control piston is manually moved in one direction or the other, there is a corresponding movement of the slave piston. A rack and gear connection between the slave piston and the mirror causes the mirror to be angularly adjusted in response to movement of the slave piston.A reversible electric motor drives the master piston through an overload slip clutch assembly.

Abstract: The invention relates to a hydraulic brake booster for a vehicle brake apparatus which is provided with a pressurizing apparatus which has a pump and a reservoir. When the reservoir pressure fails, a switchover piston which is subject to the reservoir pressure can disengage a stop for the push rod of the control valve.The push rod is supported on the stop when the pressure supply to the reservoir is intact and after the control valve switches over in the direction of brake activation, in order to give the driver a sense of the added brake force. In the same event, a support of a pedal activation stem on a movable auxiliary cylinder is removed. When the reservoir pressure supply fails, however, this support is made available, in order to enable an immediate mechanical actuation of the main cylinder portion of the brake booster.

Abstract: A sealed type fluid reservoir in which a valve member is incorporated in a main cap which is coupled with an upper end of a casing. The pressure in the interior of the casing is maintained at atmospheric level by the valve member despite pressure variation in the interior of the casing.

Abstract: The power brake includes an electric motor to provide braking power assistance actuated by a brake pedal and a transmission means interconnecting the brake pedal, the motor and a master cylinder piston, the transmission means being actuated by the brake pedal and having a frictional coupling to actuate the master cylinder piston, the friction of the frictional coupling increasing in proportion to the brake pedal pressure.

Abstract: An installation for the servo-assist of actuating devices in motor vehicles, especially of a hydraulic brake system, in which a control member, such as the brake pedal, acts on an actuating device, such as a master cylinder of a two-circuit brake system by way of a servo-member; a hydraulically actuatable servo-unit is thereby arranged between the control member and the actuating device whose first part is supported at the control member and whose second part is connected with the actuating device; the actuation of the servo-unit is controllable from a hydraulic pressure medium source in the manner of a follower control by means of a control device connected with the control member.

Abstract: A resilient seal cap is coupled over an upper opening of a reservoir casing to define an interior air space with the upper surface of brake fluid in the casing. The seal cap is formed integral with a first annular lip co-operating with the inner wall of the casing to provide an inlet check valve permitting the flow of air into the interior air space and with a second annular lip co-operating with a valve plate secured to the center of the casing to provide an outlet check valve permitting the flow of air out from the interior air space to the exterior.

Abstract: A two stage master cylinder having a bore with a first diameter and a second diameter separated by a shoulder. A first piston is located in the first diameter of the bore to establish a first chamber. A second piston has a first section located in the first diameter of the bore to establish a second chamber and a second section located in the second diameter of the bore to establish an actuation chamber therein. A first passage in the second piston connects the actuation chamber with the second chamber. A second passage in the second piston connects the first passage to a reservoir in the housing. A shuttle piston located in the first passage has a first surface area exposed to the second chamber and a second smaller surface area exposed to the actuation chamber. A spring urges the shuttle piston toward the second chamber. An input force from an operator moves the second piston causing fluid to flow from the actuation chamber through the first passage to the second chamber.

Abstract: A master cylinder for a two-circuit brake system which includes anti-skid control has two separate chambers and pistons. The main control piston is surrounded by an auxiliary piston which it engages after a predetermined amount of travel. The auxiliary piston has an extension which holds the brake control valve and which is opened by the control piston during its travel. Furthermore, the second circuit cylinder includes a pressure sensor which can activate a warning when the piston travel is not in a predetermined relation to the applied fluid pressure.

Abstract: A brake booster for a vehicle comprises first and second control pistons operated by hydraulic pressure from a master cylinder, and a power piston pneumatically actuated in response to movement of the control pistons to increase braking pressure applied to the wheel brake cylinders of the vehicle. To control the increasing ratio of the braking pressure in accordance with the changes of the vehicle weight, under unloaded condition of the vehicle only the first control piston is operated by the master cylinder pressure to actuate the power piston and under loaded condition of the vehicle the second control piston co-operates with the first control piston by the master cylinder pressure to accelerate the actuation of the power piston.

Abstract: In a sealed fluid reservoir for a hydraulic brake master cylinder, inlet and outlet check valves are compactly assembled with a reservoir cap to constantly seal brake fluid stored in the reservoir against the surrounding air. The inlet and outlet check valves are selectively opened in response to rise or drop of the level of fluid in the reservoir to ensure smooth fluid supply to the brake master cylinder.

Abstract: A master cylinder having an indicator activated by either a low level fluid condition in a reservoir or any operational pressure imbalance between first and second fluid distribution systems of a master cylinder to inform an operator of an adverse condition which could affect braking.

Abstract: A fluid motor having a housing with a stepped bore for retaining a first piston and a second piston. A sleeve is located in the stepped bore to permit the first piston and the second piston to be of substantially the same diameter. A plug attached to the housing holds the sleeve in the stepped bore. A spring attached to the sleeve holds the first piston against a stop. The spring acts on the sleeve to create a gap with a shoulder in the stepped bore. The second piston which is connected to the first piston through a linkage mechanism carries a concentric shuttle piston. The shuttle piston is subjected to a first hydraulic pressure created by the first piston and to a second hydraulic pressure created by the second piston. An indicator is connected to the shuttle piston and remains inactive when the first and second hydraulic pressures are substantially equal.

Abstract: A two-circuit master cylinder unit for brakes includes first and second cylinders and first and second pistons slidably received in the first and second cylinders, respectively. The first piston is actuated by an external force for pressurizing hydraulic fluid in the first cylinder. The second piston is exposed to a pressure which depends upon the pressure generated in the first cylinder. A shackle device which couples the first and second pistons to one another, allows a relative axial displacement of predetermined magnitude between the first and second pistons. A switching device is operatively connected to the shackle device and is actuated when the predetermined magnitude of relative displacement between the pistons is reached. A warning device is operatively connected to the switching device and responds when the switching device is actuated.

Abstract: A relay unit associated with a fluid cooled transformer apparatus. The relay utilizes an hydraulic bellows circuit system to sense internal pressure changes developing in a tank member of the transformer apparatus; and it responds to a sudden rise in the pressure to operate an alarm switch. The system includes a group of three bellows, one of which reacts to pressure changes in the tank; and the other two of which respond according to the reaction of the first in controlling operation of the switch. A pivoted bracket and supporting spring arrangement associated with the bellows serves to control operation of the switch and to restrain it from being operated by shocks and the like attendant upon seismic conditions.

Abstract: In a hydraulic brake system, a housing includes a brake master cylinder and a reservoir formed therein for containing a supply of brake fluid. A sensor piston in contact with the pressure in the brake master cylinder is connected to an indicator piston. The indicator piston is coaxial with a blind cylindrical indicator bore. The blind bore and indicator piston are in communication with the reservoir at a level below which the brake fluid should not be allowed to recede. When the brake is operated, brake master cylinder pressure urges the sensor piston outward. The connected indicator piston is urged toward the blind bore. If the reservoir contains fluid, the blind bore is filled with the fluid. Fluid lock of the indicator piston therefore occurs before any appreciable indicator piston motion into the blind indicator bore. On the other hand, if the reservoir, and the communicating indicator bore, are empty, the indicator piston is enabled to enter the indicator bore by compressing air therein.

Abstract: A device usable in a brake system including two independent hydraulic lines extending from a dual brake master cylinder to front and rear wheel brakes, respectively. The device is arranged across the two hydraulic lines midway thereof to serve the purposes of adjusting the fluid pressure ratio between the front and rear wheel brakes with a change in ratio of the vehicle load bearing on the front wheels to that on the rear wheels thereby to maximize the overall braking efficiency particularly in hard braking operations and of enabling the brake system to operate even with some fluid leakage, possibly occurring in either of the two hydraulic lines, to brake the vehicle effectively enough while at the same time warning the driver of the fluid trouble. The essential component parts, including a number of cooperating pistons and a valve associated therewith, are accommodated in a single cylinder casing and this structure renders the whole device particularly compact in size and simple in construction.

Abstract: Fluid within a pressure chamber is displaced and pressurized by reeling a flexible cable or filament into the pressure chamber. A movable piston or similar pressure-responsive member in fluid communication with the chamber is moved by the displacement of fluid in the chamber, so as to perform useful work. The flexible cable or filament is wound on a motor-driven reel located in the pressure chamber.